Multi-speed transmissions

ABSTRACT

The transmission has a plurality of members that can be utilized in powertrains to provide at least ten forward speed ratios and one reverse speed ratio. The transmission includes four planetary gear sets, six torque-transmitting devices, and three fixed interconnections. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members and the transmission housing, and are operated in combinations of three to establish at least ten forward speed ratios and one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a power transmission having fourplanetary gear sets that are controlled by six torque-transmittingdevices to provide at least ten forward speed ratios and one reversespeed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

Six-speed transmissions offer several advantages over four- andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five- or six-speed devices due to the size and complexityof these transmissions.

Seven-, eight-, nine- and ten-speed transmissions provide furtherimprovements in acceleration and fuel economy over six-speedtransmissions. However, like the six-speed transmissions discussedabove, the development of seven-, eight-, nine- and ten-speedtransmissions has been precluded because of complexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedtransmission having four planetary gear sets controlled to provide atleast ten forward speed ratios and one reverse speed ratio.

The transmission family of the present invention has four planetary gearsets, each of which includes a first, second and third member, whichmembers may comprise a sun gear, a ring gear, or a planet carrierassembly member, in any order.

In referring to the first, second, third and fourth gear sets in thisdescription and in the claims, these sets may be counted “first” to“fourth” in any order in the drawing (i.e., left to right, right toleft, etc.). Additionally, the first, second or third members of eachgear set may be counted “first” to “third” in any order in the drawing(i.e., top to bottom, bottom to top, etc.) for each gear set.

Each carrier member can be either a single-pinion carrier member(simple) or a double-pinion carrier member (compound). Embodiments withlong pinions are also possible.

The input member is continuously connected with the second member of thefourth planetary gear set. The output member is continuously connectedwith the second member of the first or third planetary gear set.

A first interconnecting member continuously connects the first or secondmember of the first planetary gear set with the second or third memberof the second planetary gear set.

A second interconnecting member continuously connects the first memberof the second planetary gear set with the first or second member of thethird planetary gear set and with the third member of the fourthplanetary gear set.

A third interconnecting member continuously connects the third member ofthe first planetary gear set with the first or third member of the thirdplanetary gear set.

A first torque-transmitting device, such as a brake, selectivelyconnects the second member of the first planetary gear set or the thirdmember of the second planetary gear set with a stationary member(transmission housing/casing).

A second torque-transmitting device, such as a brake, selectivelyconnects the first member of the fourth planetary gear set or the thirdmember of the third planetary gear set with a stationary member(transmission housing/casing).

A third torque-transmitting device, such as a clutch, selectivelyconnects the second or third member of the first planetary gear set withthe first member of the second planetary gear set or with the secondmember of the fourth planetary gear set.

A fourth torque-transmitting device, such as a clutch, selectivelyconnects the third member of the first planetary gear set or the secondmember of the second planetary gear set with the first or second memberof the fourth planetary gear set.

A fifth torque-transmitting device, such as a clutch, selectivelyconnects the third member of the second planetary gear set with thefirst member of the first or fourth planetary gear set.

A sixth torque-transmitting device, such as a clutch, selectivelyconnects the first or second member of the first planetary gear set withthe second member of the second planetary gear set or with the firstmember of the fourth planetary gear set.

The six torque-transmitting devices are selectively engageable incombinations of three to yield at least ten forward speed ratios and onereverse speed ratio.

A variety of speed ratios and ratio spreads can be realized by suitablyselecting the tooth ratios of the planetary gear sets.

The above features and other features and advantages of the presentinvention are readily apparent from the following detailed descriptionof the best modes for carrying out the invention when taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 a is a schematic representation of a powertrain including aplanetary transmission in accordance with the present invention;

FIG. 1 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1 a;

FIG. 1 c is a schematic representation of the powertrain of FIG. 1 adepicted in lever diagram form;

FIG. 2 a is a schematic representation of a powertrain including aplanetary transmission incorporating another family member of thepresent invention;

FIG. 2 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2 a; and

FIG. 2 c is a schematic representation of the powertrain of FIG. 2 adepicted in lever diagram form.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, there is shown in FIG. 1 a a powertrain 10having a conventional engine and torque converter 12, a planetarytransmission 14, and a conventional final drive mechanism 16. The engine12 may be powered using various types of fuel to improve the efficiencyand fuel economy of a particular application. Such fuels may include,for example, gasoline; diesel; ethanol; dimethyl ether; etc.

The planetary transmission 14 includes an input member 17 continuouslyconnected with the engine 12, a planetary gear arrangement 18, and anoutput member 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 18 includes four planetary gear sets20, 30, 40 and 50.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly member 26. The planet carrierassembly member 26 includes a plurality of pinion gears 27 rotatablymounted on a carrier member 29 and disposed in meshing relationship withboth the sun gear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 mounted on acarrier member 49 and disposed in meshing relationship with both thering gear member 44 and the sun gear member 42.

The planetary gear set 50 includes a sun gear member 52, a ring gearmember 54, and a planet carrier assembly member 56. The planet carrierassembly member 56 includes a plurality of pinion gears 57 mounted on acarrier member 59 and disposed in meshing relationship with both thering gear member 54 and the sun gear member 52.

The planetary gear arrangement also includes six torque-transmittingdevices 80, 82, 84, 85, 86 and 87. The torque-transmitting devices 80and 82 are stationary-type torque-transmitting devices, commonly termedbrakes or reaction clutches. The torque-transmitting devices 84, 85, 86and 87 are rotating-type torque-transmitting devices, commonly termedclutches.

The input member 17 is continuously connected with the planet carrierassembly member 56 of the planetary gear set 50. The output member 19 iscontinuously connected with the planet carrier assembly member 46 of theplanetary gear set 40.

A first interconnecting member 70 continuously connects the sun gearmember 22 of the planetary gear set 20 with the ring gear member 34 ofthe planetary gear set 30. A second interconnecting member 72continuously connects the sun gear member 32 of the planetary gear set30 with the sun gear member 42 of the planetary gear set 40 and with thering gear member 54 of the planetary gear set 50. A thirdinterconnecting member 74 continuously connects the ring gear member 24of the planetary gear set 20 with the ring gear member 44 of theplanetary gear set 40.

A first torque-transmitting device, such as brake 80, selectivelyconnects the planet carrier assembly member 26 of the planetary gear set20 with the transmission housing 60. A second torque-transmittingdevice, such as brake 82, selectively connects the sun gear member 52 ofthe planetary gear set 50 with the transmission housing 60. A thirdtorque-transmitting device, such as clutch 84, selectively connects theplanet carrier assembly member 26 of the planetary gear set 20 with thesun gear member 32 of the planetary gear set 30, the sun gear member 42of the planetary gear set 40 and the ring gear member 54 of theplanetary gear set 50 via interconnecting member 72. A fourthtorque-transmitting device, such as clutch 85, selectively connects theplanet carrier assembly member 36 of the planetary gear set 30 with theplanet carrier assembly member 56 of the planetary gear set 50. A fifthtorque-transmitting device, such as clutch 86, selectively connects thering gear member 34 of the planetary gear set 30 and the sun gear member22 of the planetary gear set 20 via interconnecting member 70 with thesun gear member 52 of the planetary gear set 50. A sixthtorque-transmitting device, such as clutch 87, selectively connects theplanet carrier assembly member 26 of the planetary gear set 20 with theplanet carrier assembly member 36 of the planetary gear set 30.

As shown in FIG. 1 b, and in particular the truth table disclosedtherein, the torque-transmitting devices are selectively engaged incombinations of three to provide ten forward speed ratios and onereverse speed ratio, all with single transition sequential shifts andfour overdrive ratios.

As set forth above, the engagement schedule for the torque-transmittingdevices is shown in the truth table of FIG. 1 b. The chart of FIG. 1 bdescribes the ratio steps that are attained in the above describedtransmission. For example, the step ratio between the first and secondforward speed ratios is 1.67, while the step ratio between the reversespeed ratio and first forward ratio is −0.83.

Referring to FIG. 1 c, the embodiment of powertrain 10 depicted in FIG.1 a is illustrated in a lever diagram format. A lever diagram is aschematic representation of the components of a mechanical device suchas an automatic transmission. Each individual lever represents aplanetary gearset, wherein the three basic mechanical components of theplanetary gear are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear member, one for the planetgear carrier member, and one for the ring gear member. The relativelength between the nodes of each lever can be used to represent thering-to-sun ratio of each respective gearset. These lever ratios, inturn, are used to vary the gear ratios of the transmission in order toachieve appropriate ratios and ratio progression. Mechanical couplingsor interconnections between the nodes of the various planetary gear setsare illustrated by thin, horizontal lines and torque transmittingdevices such as clutches and brakes are presented as interleavedfingers. If the device is a brake, one set of the fingers is grounded.Further explanation of the format, purpose and use of lever diagrams canbe found in SAE Paper 810102, authored by Benford, Howard and Leising,Maurice, “The Lever Analogy: A New Tool in Transmission Analysis”, 1981,which is hereby fully incorporated by reference.

The powertrain 10 includes an input member 17 continuously connectedwith the engine 12, an output member 19 continuously connected with thefinal drive mechanism 16, a first planetary gear set 20A having threenodes: a first node 22A, a second node 26A and a third node 24A; asecond planetary gear set 30A having three nodes: a first node 32A, asecond node 36A and a third node 34A; a third planetary gear set 40Ahaving three nodes: a first node 42A, a second node 46A and a third node44A; and a fourth planetary gear set 50A having three nodes: a firstnode 52A, a second node 56A and a third node 54A.

The input member 17 is continuously connected with the node 56A. Theoutput member 19 is continuously connected with the node 46A.

The node 22A is continuously connected with node 34A via interconnectingmember 70. The node 32A is continuously connected with nodes 42A and 54Avia interconnecting member 72. The node 24A is continuously connectedwith node 44A via interconnecting member 74.

A first torque-transmitting device, such as brake 80, selectivelyconnects the node 26A with the transmission housing 60. A secondtorque-transmitting device, such as brake 82, selectively connects thenode 52A with the transmission housing 60. A third torque-transmittingdevice, such as clutch 84, selectively connects the nodes 32A, 42A and54A via interconnecting member 72 with the node 26A. A fourthtorque-transmitting device, such as clutch 85, selectively connects thenode 36A with the node 56A. A fifth torque-transmitting device, such asclutch 86, selectively connects the nodes 34A and 22A viainterconnecting member 70 with the node 52A. A sixth torque-transmittingdevice, such as clutch 87, selectively connects the node 26A with thenode 36A.

To establish ratios, three torque-transmitting devices are engaged foreach gear state. The engaged torque-transmitting devices are representedby an “X” in each respective row of FIG. 1 b. For example, to establishreverse gear, the brake 80 and clutches 84, 85 are engaged. The brake 80engages the node 26A with the transmission housing 60. The clutch 84engages the nodes 32A, 42A and 54A via interconnecting member 72 withthe node 26A. The clutch 85 engages the node 36A with the node 56A.Likewise, the ten forward ratios are achieved through differentcombinations of clutch engagement as per FIG. 1 b.

The powertrain 10 and powertrain 110 described below may sharecomponents with a hybrid vehicle, and such a combination may be operablein a “charge-depleting mode”. For purposes of the present invention, a“charge-depleting mode” is a mode wherein the vehicle is poweredprimarily by an electric motor/generator such that a battery is depletedor nearly depleted when the vehicle reaches its destination. In otherwords, during the charge-depleting mode, the engine 12 is only operatedto the extent necessary to ensure that the battery is not depletedbefore the destination is reached. A conventional hybrid vehicleoperates in a “charge-sustaining mode”, wherein if the battery chargelevel drops below a predetermined level (e.g., 25%) the engine isautomatically run to recharge the battery. Therefore, by operating in acharge-depleting mode, the hybrid vehicle can conserve some or all ofthe fuel that would otherwise be expended to maintain the 25% batterycharge level in a conventional hybrid vehicle. It should be appreciatedthat a hybrid vehicle powertrain is preferably only operated in thecharge-depleting mode if the battery can be recharged after thedestination is reached by plugging it into an energy source.

DESCRIPTION OF A SECOND EXEMPLARY EMBODIMENT

In FIG. 2 a a powertrain 110 is shown having a conventional engine andtorque converter 12, a planetary transmission 114, and a conventionalfinal drive mechanism 16. The engine 12 may be powered using varioustypes of fuel to improve the efficiency and fuel economy of a particularapplication. Such fuels may include, for example, gasoline; diesel;ethanol; dimethyl ether; etc.

The planetary transmission 114 includes an input member 17 continuouslyconnected with the engine 12, a planetary gear arrangement 118, and anoutput member 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 118 includes four planetary gear sets120, 130, 140 and 150.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly member 126. The planet carrierassembly member 126 includes a plurality of pinion gears 127 rotatablymounted on a carrier member 129 and disposed in meshing relationshipwith both the sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear members 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 mounted ona carrier member 149 and disposed in meshing relationship with both thering gear member 144 and the sun gear member 142.

The planetary gear set 150 includes a sun gear member 152, a ring gearmember 154, and a planet carrier assembly member 156. The planet carrierassembly member 156 includes a plurality of pinion gears 157 mounted ona carrier member 159 and disposed in meshing relationship with both thering gear member 154 and the sun gear member 152.

The planetary gear arrangement also includes six torque-transmittingdevices 180, 182, 184, 185, 186 and 187. The torque-transmitting devices180 and 182 are stationary-type torque-transmitting devices, commonlytermed brakes or reaction clutches. The torque-transmitting devices 184,185, 186 and 187 are rotating-type torque-transmitting devices, commonlytermed clutches.

The input member 17 is continuously connected with the planet carrierassembly member 156 of the planetary gear set 150. The output member 19is continuously connected with the planet carrier assembly member 136 ofthe planetary gear set 130.

A first interconnecting member 170 continuously connects the planetcarrier assembly member 126 of the planetary gear set 120 with theplanet carrier assembly member 136 of the planetary gear set 136. Asecond interconnecting member 172 continuously connects the sun gearmember 132 of the planetary gear set 130 with the planet carrierassembly member 146 of the planetary gear set 140 and with the ring gearmember 154 of the planetary gear set 150. A third interconnecting member174 continuously connects the ring gear member 124 of the planetary gearset 120 with the sun gear member 142 of the planetary gear set 140.

A first torque-transmitting device, such as brake 180, selectivelyconnects the ring gear member 134 of the planetary gear set 130 with thetransmission housing 160. A second torque-transmitting device, such asbrake 182, selectively connects the ring gear member 144 of theplanetary gear set 140 with the transmission housing 160. A thirdtorque-transmitting device, such as clutch 184, selectively connects thering gear member 124 of the planetary gear set 120 and sun gear member142 of the planetary gear set 140 via interconnecting member 174 withthe planet carrier assembly member 156 of the planetary gear set 150. Afourth torque-transmitting device, such as clutch 185, selectivelyconnects the ring gear member 124 of the planetary gear set 120 and sungear member 142 of the planetary gear set 140 via interconnecting member174 with the sun gear member 152 of the planetary gear set 150. A fifthtorque-transmitting device, such as clutch 186, selectively connects thesun gear member 122 of the planetary gear set 120 with the ring gearmember 134 of the planetary gear set 130. A sixth torque-transmittingdevice, such as clutch 187, selectively connects the sun gear member 122of the planetary gear set 120 with the sun gear member 152 of theplanetary gear set 150.

As shown in FIG. 2 b, and in particular the truth table disclosedtherein, the torque-transmitting devices are selectively engaged incombinations of three to provide fourteen forward speed ratios and onereverse speed ratio, all with single transition sequential shifts andfive overdrive ratios.

As set forth above, the engagement schedule for the torque-transmittingdevices is shown in the truth table of FIG. 2 b. The chart of FIG. 2 bdescribes the ratio steps that are attained in the above describedtransmission. For example, the step ratio between the first and secondforward speed ratios is 1.68, while the step ratio between the reversespeed ratio and first forward ratio is −0.77.

Referring to FIG. 2 c, the embodiment of powertrain 110 depicted in FIG.2 a is illustrated in a lever diagram format. The powertrain 110includes an input member 17 continuously connected with the engine 12,an output member 19 continuously connected with the final drivemechanism 16, a first planetary gear set 120A having three nodes: afirst node 122A, a second node 126A and a third node 124A; a secondplanetary gear set 130A having three nodes: a first node 132A, a secondnode 136A and a third node 134A; a third planetary gear set 140A havingthree nodes: a first node 142A, a second node 146A and a third node144A; and a fourth planetary gear set 150A having three nodes: a firstnode 152A, a second node 156A and a third node 154A.

The input member 17 is continuously connected with the node 156A. Theoutput member 19 is continuously connected with the nodes 126A and 136A.

The node 126A is continuously connected with node 136A viainterconnecting member 170. The node 132A is continuously connected withthe nodes 146A and 154A via interconnecting member 172. The node 124A iscontinuously connected with the node 142A via interconnecting member174.

A first torque-transmitting device, such as brake 180, selectivelyconnects the node 134A with the transmission housing 160. A secondtorque-transmitting device, such as brake 182, selectively connects thenode 144A with the transmission housing 160. A third torque-transmittingdevice, such as clutch 184, selectively connects the nodes 124A and 142Avia interconnecting member 174 with the node 156A. A fourthtorque-transmitting device, such as clutch 185, selectively connects thenodes 124A and 142A via interconnecting member 174 with the node 152A. Afifth torque-transmitting device, such as clutch 186, selectivelyconnects the node 122A with the node 134A. A sixth torque-transmittingdevice, such as clutch 187, selectively connects the node 122A with thenode 152A.

To establish ratios, three torque-transmitting devices are engaged foreach gear state. The engaged torque-transmitting devices are representedby an “X” in each respective row of FIG. 2 b. For example, to establishreverse gear, the brakes 180, 182 and clutch 187 are engaged. The brake180 engages the node 134A with the transmission housing 160. The brake182 engages the node 144A with the transmission housing 160. The clutch187 engages the node 122A with the node 152A. Likewise, the fourteenforward ratios are achieved through different combinations of clutchengagement as per FIG. 2 b.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input member; an outputmember; first, second, third and fourth planetary gear sets each havingfirst, second and third members; a first interconnecting membercontinuously connecting said first or said second member of said firstplanetary gear set with said second or said third member of said secondplanetary gear set; a second interconnecting member continuouslyconnecting said first member of said second planetary gear set with saidfirst or said second member of said third planetary gear set and withsaid third member of said fourth planetary gear set; a thirdinterconnecting member continuously connecting said third member of saidfirst planetary gear set with said first or said third member of saidthird planetary gear set; and six torque-transmitting devices beingengaged in combinations of three to establish at least ten forward speedratios and at least one reverse speed ratio between said input memberand said output member.
 2. The transmission of claim 1, wherein a firstof said six torque-transmitting devices selectively connects said secondmember of said first planetary gear set or said third member of saidsecond planetary gear set with a stationary member.
 3. The transmissionof claim 2, wherein a second of said six torque-transmitting devicesselectively connects said first member of said fourth planetary gear setor said third member of said third planetary gear set with saidstationary member.
 4. The transmission of claim 3, wherein a third ofsaid six torque-transmitting devices selectively connects said second orsaid third member of said first planetary gear set with said firstmember of said second planetary gear set or with said second member ofsaid fourth planetary gear set.
 5. The transmission of claim 4, whereina fourth of said six torque-transmitting devices selectively connectssaid first or said second member of fourth planetary gear set with saidsecond member of said second planetary gear set or with said firstmember of said first planetary gear set.
 6. The transmission of claim 5,wherein a fifth of said six torque-transmitting devices selectivelyconnects said third member of said second planetary gear set with saidfirst member of said first or said fourth planetary gear set.
 7. Thetransmission of claim 6, wherein a sixth of said six torque-transmittingdevices selectively connects said first or said second member of saidfirst planetary gear set with said second member of said secondplanetary gear set or with said first member of said fourth planetarygear set.
 8. The transmission of claim 7, wherein said input member iscontinuously connected with said second member of said fourth planetarygear set; and said output member is continuously connected with saidsecond member of said first or said third planetary gear set.
 9. Thetransmission of claim 8, wherein said first, second and third members ofsaid first, second, third and fourth planetary gear sets comprise a sungear member, a planet carrier assembly member and a ring gear member,respectively.
 10. The transmission of claim 1, wherein said input memberis continuously connected with said second member of said fourthplanetary gear set; said output member is continuously connected withsaid second member of said third planetary gear set; said firstinterconnecting member continuously connects said first member of saidfirst planetary gear set with said third member of said second planetarygear set; said second interconnecting member continuously connects saidfirst member of said second planetary gear set with said first member ofsaid third planetary gear set and with said third member of said fourthplanetary gear set; said third interconnecting member continuouslyconnects said third member of said first planetary gear set with saidthird member of said third planetary gear set; said firsttorque-transmitting device selectively connects said second member ofsaid first planetary gear set with said stationary member; said secondtorque-transmitting device selectively connects said first member ofsaid fourth planetary gear set with said stationary member; said thirdtorque-transmitting device selectively connects said second member ofsaid first planetary gear set with said first member of said secondplanetary gear set said fourth torque-transmitting device selectivelyconnects said second member of said second planetary gear set with saidsecond member of said fourth planetary gear set; said fifthtorque-transmitting device selectively connects said third member ofsaid second planetary gear set with said first member of said fourthplanetary gear set; and said sixth torque-transmitting deviceselectively connects said second member of said first planetary gear setwith said second member of said second planetary gear set.
 11. Thetransmission of claim 1, wherein said input member is continuouslyconnected with said second member of said fourth planetary gear set;said output member is continuously connected with said second member ofsaid first planetary gear set; said first interconnecting membercontinuously connects said second member of said first planetary gearset with said second member of said second planetary gear set; saidsecond interconnecting member continuously connects said first member ofsaid second planetary gear set with said second member of said thirdplanetary gear set and with said third member of said fourth planetarygear set; said third interconnecting member continuously connects saidthird member of said first planetary gear set with said first member ofsaid third planetary gear set; said first torque-transmitting deviceselectively connects said third member of said second planetary gear setwith said stationary member; said second torque-transmitting deviceselectively connects said third member of said third planetary gear setwith said stationary member; said third torque-transmitting deviceselectively connects said third member of said first planetary gear setwith said second member of said fourth planetary gear set; said fourthtorque-transmitting device selectively connects said third member ofsaid first planetary gear set with said first member of said fourthplanetary gear set; said fifth torque-transmitting device selectivelyconnects said first member of said first planetary gear set with saidthird member of said second planetary gear set; and said sixthtorque-transmitting device selectively connects said first member ofsaid first planetary gear set with said first member of said fourthplanetary gear set.
 12. The transmission of claim 10, wherein saidfirst, second and third members of said first, second, third and fourthplanetary gear sets comprise a sun gear member, a planet carrierassembly member and a ring gear member, respectively.
 13. Thetransmission of claim 11, wherein said first, second and third membersof said first, second, third and fourth planetary gear sets comprise asun gear member, a planet carrier assembly member and a ring gearmember, respectively.
 14. A multi-speed transmission comprising: aninput member; an output member; first, second, third and fourthplanetary gear sets each having first, second and third members; a firstinterconnecting member continuously connecting said first or said secondmember of said first planetary gear set with said second or said thirdmember of said second planetary gear set; a second interconnectingmember continuously connecting said first member of said secondplanetary gear set with said first or said second member of said thirdplanetary gear set and with said third member of said fourth planetarygear set; a third interconnecting member continuously connecting saidthird member of said first planetary gear set with said first or saidthird member of said third planetary gear set; a firsttorque-transmitting device selectively connecting said second member ofsaid first planetary gear set or said third member of said secondplanetary gear set with a stationary member; a secondtorque-transmitting device selectively connecting said first member ofsaid fourth planetary gear set or said third member of said thirdplanetary gear set with said stationary member; a thirdtorque-transmitting device selectively connecting said second or saidthird member of said first planetary gear set with said first member ofsaid second planetary gear set or with said second member of said fourthplanetary gear set; a fourth torque-transmitting device selectivelyconnecting said first or said second of said fourth planetary gear setwith said second member of said second planetary gear set or said thirdmember of said first planetary gear set; a fifth torque-transmittingdevice selectively connecting said third member of said second planetarygear set with said first member of said first or said fourth planetarygear set; a sixth torque-transmitting device selectively connecting saidfirst or said second member of said first planetary gear set with saidsecond member of said second planetary gear set or said first member ofsaid fourth planetary gear set; and said six torque-transmitting devicesbeing engaged in combinations of three to establish at least ten forwardspeed ratios and at least one reverse speed ratio between said inputmember and said output member.
 15. The transmission of claim 14, whereinsaid first, second and third members of said first, second, third andfourth planetary gear sets comprise a sun gear member, a planet carrierassembly member and a ring gear member, respectively.